Hi Jerry!
What you mentioned was a part of the problem!
Due to the quit mode it's indeed very hard to find what has been backed up. I 
checked the amount of files inspected (like you suggested) and last night it 
was correct!
The actual cause why the drive wasn't backed up was that the SYSTEM account had 
no access to the drive's root. I gave the SYSTEM account 'full access' to D:\ 
and this solved my problem.
Thank you all for helping me!!!
Kindest regards,
Eric van Loon